A 7-year-old Brooklyn girl is miraculously alive and well today after plummeting three stories — thanks to a heroic neighbor who raced into action and broke her fall.

Cops said little Keyla McCree pushed out one of the accordion pieces that was holding a brand- new air conditioner in a bedroom window of her Coney Island apartment and squeezed through the tiny opening before she fell off.

“She’s fine,” said the autistic girl’s mom, Shaleema McCree.

“Not a scratch on her. The man caught her, thank God.

“It’s a miracle.”

Dramatic cellphone video of Steven St. Bernard’s dramatic rescue shows a shoe-string catch that would make the Giants’ Victor Cruz proud.